A fan is the main heat sink in an electrical product. When the temperature of the electrical product is higher than a certain temperature, the fan is triggered to dissipate the heat in order to reduce the temperature. Once the temperature of the electrical product is under the certain temperature, the fan is stopped.
Typically, a fan is assembled into a system to prevent the system from crashing as a result of high temperatures. A device with a higher calculating speed requires a fan with a higher rotational speed. With a higher rotational speed comes greater difficulty in stopping a fan quickly. That is, even after cutting off power to the fan, the fan continues to rotate by inertia for some time before finally being overcome by friction.
Unfortunately, such inertial rotation generates a lot of problems. Oftentimes, a user ignores the inertial rotating state of the fan and injures himself by carelessly touching the fan. Furthermore, in routine diagnostic work, waiting for the fan to stop rotating is the bottleneck of improving work efficiency.